*Keys to the game: The Colts are riding a wave of confidence with impressive victories over San Francisco and Seattle sandwiched around a walkover in Jacksonville. While QB Andrew Luck is the face of the franchise, it's the ground game that quietly sets the table. The Colts have rushed for more than 100 yards in each of their first five games, tying a franchise record. San Diego allows an average of 117.2 yards per game on the ground, while Indianapolis is second in the NFL with nine scoring drives of 80-plus yards. San Diego has a minus-8 turnover margin with QB Philip Rivers alternating between magical and maddening. Young WRs Vincent Brown and Keenan Allen are showing promising development, but must be on point with their route-running and be on the same page with Rivers. With RB Ryan Matthews (concussion) uncertain, the brunt of the workload could again fall on Danny Woodhead and Ronnie Brown.

*Matchup to watch - Colts OLB Erik Walden vs. Chargers LT Nick Becton: If King Dunlap can't return from a concussion, the Chargers are down to their third-string blind-side protector with Mike Harris placed on injured reserve. Walden, signed away from Green Bay, is yet to register a sack this season.

*Player spotlight - Colts CB Darius Butler: The team's nickel back has interceptions in each of the past two games, providing much-needed playmaking depth for the secondary.

*Fast facts: The Colts are in sole possession of first place in the AFC South for the first time since the end of the 2010 season. ... Chargers defensive coordinator John Pagano is the younger brother of Colts head coach Chuck Pagano

WHO WILL WIN AND WHY

The Chargers remain an enigma - blowing leads against Houston and Tennessee and coming out flat against rival Oakland. Yet, they have also waxed Philadelphia on the road and beat Dallas at home. The Colts are young, confident and too well-coached to suffer a letdown.